Electrostatographic apparatus with air baffle

ABSTRACT

In an electrostatographic apparatus wherein toner images are transferred from a first imaging support to a second flexible support with a transfer corona generator, past which said second support is transported on the first support, and wherein an air puffer assists in peeling the second support from the first support by air injection against the second support; the improvement comprising an air baffle positioned between the transfer corona generator and the puffer for impeding the air from said puffer from deflecting the second support adjacent the transfer corona generator, thereby reducing toner smearing.

United States Patent [191 Inoue ELECTROSTATOGRAPHIC APPARATUS WITH AIR BAFFLE Inventor: Noriyuki lnoue, Ebina, Japan Assignee: Xerox Corporation, Stamford,

Conn.

Filed: May 21, 1973 Appl. No; 362,597

Foreign Application Priority Data June I9, 1972 Japan 47-71376 US. Cl 271/80, 271/195, 271/DIG. 2, 355/3 Int. Cl B65h 29/56 'Field'of Search 27l/DIG. 2, 195, 194, 80,

References Cited UNITED STATES PATENTS 4/1968' Draugelis 27l/5l 3,575,502 4/1971 Eppe.... ass/3 Primary Examiner-Even C. Blunk Assistant Examiner-Bruce H. Stoner, Jr.

[57] ABSTRACT In an electrostatographic apparatus wherein toner images are transferred from a first imaging support to a second flexible support with a transfer corona generator, past which said second support is transported on the first support, and wherein an air puffer assists in peeling the second support from the first support by air injection against the second support; the improvement comprising an air baffle positioned between the transfer corona generator and the puffer for impeding the air from said puffer from deflecting the second support adjacent the transfer corona generator, thereby reducing toner smearing.

9 Claims, 3 Drawing Figures May 21, 1974 I ELECTROSTATOGRAPHIC APPARATUS WITH AIR BAFFLE This invention relates to electrostatographic apparatus, and in particular to means for transferring imaging materials therein from one support surface to another.

quently, the powder image thus formed is transferred at a transfer station 5 onto a transfer medium 7, such as paper, which is fed from a supply source 6 synchronously with the position of the powder image on the powder image formation member 2.

Since the powder image formation member 2 and the transfer medium 7 electrostatically adhere to each other, it is imperative topeel the transfer medium 7 away from the member 2. One way in which this has been conventionally commercially provided is by injecting an instantaneous puff or blast of air at the leading edge of the transfer medium 7 by means of a peeling device, Le, a puffer 8. The transfer medium 7 thus separated is then brought into close contact with a conveyor belt 9 by vacuum suction or other suitable means (not shown), so as to be transferred to a succeeding process (fusing of the transferred toner material).

Examples of previously published patents further dis closing these conventional steps and apparatus, including such puffer sheet stripping devices, are illustrated in the following issued U.S. Patents and their foreign equivalents: U.S. Pat. Nos.: 3,062,536 to .I. Rutkus et 'al., issued Nov. 6, 1962; 3,339,069 to T. F. Hayne et al., issued Aug. 29, 1967; and 3,357,400 to A. T. Manghirmalani, issued Dec. 12, 1967. These patents are hereby incorporated by reference herein.

Conventional xerographic appparatus as described above has the drawbackthat, in the separation of the transfer medium 7 from the member 2 by the means of the puffer 8, the impact due to the instantaneous air injection which is applied to the transfer medium 7 by the puffer 8 reaches a position'beneath the transfer corotron 5 within the transfer station, whereupon the transfer medium 7 is subjected to vibration during the transfer process, leading to an image distortion or collapse called smear.

It is an object of this invention to provide an electrostatic machine free from the above-discussed drawback attributable to the puffer and characterized in that a baffle is provided between the transfer corotron and the puffer, such baffle being adapted to prevent the air injection impact on the transfer medium 7 from further extending to a position above the transfer corotron 5.

Referring to the drawings: 7 FIG. 1 is a schematic view of an otherwise conventional exemplary xerographic machine in accordance with the present invention, showing the status of the transfer medium just prior to its being subjected to air injection by the pufier;

FIG. 2 is the same basic view of the embodiment of FIG. 1, illustrating the state of the transfer medium after it has been subjected to air injection by the operation of the puffer; and

FIG. 3 shows an alternative embodiment, identical to the embodiment of FIGS. 1 and 2 except for a difference in the air baffle configuration.

The following description, except as specifically noted, applies to the embodiment of FIGS. 1 and 2 as well as the embodiment of FIG. 3. The difference is in the baffle 10 of FIGS. 1 and 2 in contrast to the baffle 11 of FIG. 3.

As discussed above, the baffle 10 or 11 is adapted to prevent the air injection impact from the puffer 8 from acting on the transfer medium 7 in the transfer station. The baffle 10 or 11 used for such impact prevention is attached at a position confronting the powder image formation member 2 which either presses the transfer medium 7 against the powder image formation member 2 (as in the embodiment of FIGS. 1 and 2), or leaves a small spacing therebetween to the extent that the transfer medium 7 is restrained in close contact with the member 2 near the side of the transfer corotron 5 (as in the embodiment of FIG. 3).

The baffle l0 or ll is preferably made of a sheet of polyvinylchloride or fluorine rubber or a thin metallic plate, all of which preferably have an applied Teflon coating. It has been experimentally proven that the higher the insulating property, the more efficient the baffle is.

In the embodiment of FIGS. 1 and 2, a Mylar sheet of 0.3 millimeter thickness was employed as a baffle 10. The baffle 10 was disposed such that the transfer medium 7 was slightly pressed by the baffle 10 to the powder image formation member 2. With such an arrangement smear was completely eliminated. The impact generated by the puffer 8 was thwarted by the baffle sheet 10, and no longer reached the transfer position.

In the embodiment of FIG. 3, an acrylic sheet of 0.8 millimeter thickness was used as a baffle 11. The baffle 11 was positioned so as to leave a spacing of about 1 milliimeter between the member 2 and the baffle 11. With such provisions, smear did not arise. In this case it was found that the spacing of l millimeter was sufficient to accomplish the absorption of the injection impact from the puffer 8.

It is obvious that the materials of the baffle 10' or 11 and the manner of attachment thereof used in these two embodiments is not limited in any way.

It will be apparent from the foregoing description that in electrostatographic machines relating to this invention that the provision of a baffle attached between the transfer corotron and the puffer so as to absorb the impact resulting from the air injection against the transfer medium will achieve the elimination of toner smear. In addition, this provision produces another effect in that the distance or area of adhesion between the powder image formation member and the transfer medium is greatly increased, thereby improving the transfer efficiency.

What is claimed is:

1. In an electrostatographic apparatus wherein image development material is transferred from a first imaging support to a second flexible support with transfer corona means past which said second support is transported on said first support, and wherein a puffer means assists in peeling the second support from the first support by airoform injection against said second support; the improvement comprising baffle means positioned between said transfer corona means and said puffer means for impeding said airoform injection from said puffer means against said second support adjacent said transfer corona means.

2. The apparatus of claim 1 wherein said baffle means comprises a flexible shield mounted to said transfer corona means facing said puffer means and extending toward said first support.

3. The apparatus of claim 1 wherein said baffle means engages said first support for slightly pressing said second support against said first support.

4. The apparatus of claim 1 wherein said baffle means is a thin insulative air shield plate.

5. The apparatus of claim 1 wherein said baffle means is a insulative shield mounted adjacent said ter of said first support. I

transfer corona means and extending to closely adjacent said first support for restricting the movement of said second support away from said first support adjacent said transfer corona means.

6. The apparatus of claim 5 wherein said baffle means is mounted to one side of said transfer corona means.

7. The apparatus of claim 5 wherein said baffle means is a thin non-metalic plate.

8. The apparatus of claim 7 wherein said baffle means engages said first support for slightly pressing said second support against said first support.

9. The apparatus of claim 5 wherein said baffle means is positioned to within approximately 1 millime- 

1. In an electrostatographic apparatus wherein image development material is transferred from a first imaging support to a second flexible support with transfer corona means past which said second support is transported on said first support, and wherein a puffer means assists in peeling the second support from the first support by airoform injection against said second support; the improvement comprising baffle means positioned between said transfer corona means and said puffer means for impeding said airoform injection from said puffer means against said second support adjacent said transfer corona means.
 2. The apparatus of claim 1 wheRein said baffle means comprises a flexible shield mounted to said transfer corona means facing said puffer means and extending toward said first support.
 3. The apparatus of claim 1 wherein said baffle means engages said first support for slightly pressing said second support against said first support.
 4. The apparatus of claim 1 wherein said baffle means is a thin insulative air shield plate.
 5. The apparatus of claim 1 wherein said baffle means is a insulative shield mounted adjacent said transfer corona means and extending to closely adjacent said first support for restricting the movement of said second support away from said first support adjacent said transfer corona means.
 6. The apparatus of claim 5 wherein said baffle means is mounted to one side of said transfer corona means.
 7. The apparatus of claim 5 wherein said baffle means is a thin non-metalic plate.
 8. The apparatus of claim 7 wherein said baffle means engages said first support for slightly pressing said second support against said first support.
 9. The apparatus of claim 5 wherein said baffle means is positioned to within approximately 1 millimeter of said first support. 